Electrical aerial advertising sign



Nov. 11, 1930. R. ROHLFS ELECTRICAL AERIAL ADVERTISING SIGN Filed Aug. 8, 1925 2 Sheets-Sheet l INVENTOR EoLAH D Eon-1 F5.

A ORNEY Nov. 11, 1930. 'R. ROHLFS ELECTRICAL AERIAL ADVERTISING SIGN Filed Aug. 8, 1925 2 Sheets-Sheet 2 v R O T m V m 1 4. 2 2 O 2 ROLAND Ror-lLFs ATT RNEY Patented Nov. 11, 1930 UNITED STATES PATENT OFFICE ROLAND ROHLFS, OF FOREST HILLS, NEW YORK, ASSIGNOR, BY DIRECT AND MESNE AS- SIGNMENTS, TO AERIAL ADVERTISING, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY ELECTRICAL AERIAL ADVERTISING SIGN Application filed August 8, 1925. Serial No. 48,933.

My invention relates to night aerial advertising and is concerned more particularly with electrical advertising signs or the like so constructed and operated as to render practical its or their use on or in connection with aircraft.

The use of electrical advertising signs on aircraft for night aerial advertising purposes is not a new idea. Many attempts have heretofore been made to advertise goods or merchandise by such use. In every attempt (prior to the present invention) the conventional type electrical advertising sign has been employed. Such a sign is, for many reasons, wholly impractical and wholly unsuited to aerial use. .It includes, among other things, a multiplicity of incandescent lamps or bulbs, suitable light reflectors and a plurality of storage batteries suflicient in strength and number to operate the multiple lamps. The storage batteries, lamps and reflectors, and especially the former, are exceedingly heavy devices. The lamps and reflectors are necessarily exposed and are accordingly flight resistant. Their collective resistance is in fact enormous. Such resistance, coupled with the weight increase, when added to the resistance and weight of the airplane(or other craft) itself, renders it (the' airplane) dangerous in operation. Maximum power is required, even under the most favorable conditions, to sustain the machine in the air. Its ceiling is very appreciably reduced and forced landings are the rule rather than the exception. Moreover, the use of lamps and reflectors on the underside of an airplane wing very appreciably reduce its lifting efliciency.

Aside from aerodynamical considerations, incandescent lamps or bulbs for night aerial advertising purposes, are still further objectionable. The light produced is both diffused and glaring, the glare being accentuated by the use of reflectors. At elevations exceeding several hundred feet the illuminated letters, or other characters comprising the sign (unless inordinately large) cannot be read or deciphered with the naked eye by persons standing on the earth beneath. That which is intended to be a legible sign appears to the observer to be nothing more or less than a light mass or body of light.

Low altitude flying, with any machine, and especially with a sluggish machine or a machine loaded to the limit, is an extremely hazardous undertaking. It is even more hazardous where the flying is of necessity confined to areas over thickly populated centers. Notwithstanding such danger, if a legible display of the conventional type electrical advertising sign is desired, low altitude flying must be persistently and repeatedly achieved. The impracticability of night aerial advertising as heretofore attempted is accordingly at once apparent.

The present invention,as distinguished from that, which is old and impractical, is primarily dependent for its successful operation upon a distinctly novel and advantageous combination of several devices. Instead of using, as an illuminating means, a multiplicity of incandescent lamps or bulbs, one or more so-called Neon luminous tube-lights are employed. These tubes, one for each letter or other character comprised in the sign, (altho two or more can be used if the sign is exceedingly large), are formed from a single length of transparent glass or other translucent material. Before installation, each tube is permanently shaped or formed to present .each instance being in turn electrically connected with a common sourceof electrical current supply. Neon luminous tube-lights, in

addition to being extremely economical of operation, produce when active, a highly penetrating, non-glaring and continuous or unbroken light.- That is to say, each letter or character, within certain limits, being formed from a single length of tubing, is

constituent is requiredlto be used in the attainment of the resulting light.

In addition to being vastly superior to mcandescent electric lamps inso far as the character of light produced is concerned, Neon luminous tube-lights are of exceedingly light vaeight, are of a good streamline shape, and are of comparatively small diameter. Being light, streamlined and of small diameter, such tubes naturally lend themselves admirably to use upon aircraft. The length of tube required for any given letter approximately 5' inlength by 3' in width weighs approximately two pounds in all. Its diameter, for all practical purposes, should not exceed fifteen (15) millimeters it having been found upon test that a tube ofthis' size is clearly visible when illuminated atan altitude of upwards of 2000 feet. A sign thus characterized, even tho exposed, offers a minimum of resistance in flight. Its smallness and cleancut outline have but little or no effect in diminishingthe lifting efliciency of the wing. Its ruggedness and serviceability make it especially desirable in that no harmful effects have been found to exist as a result of the continuous and incessant vibrations caused by the operation of an aircraft both prior to and during actual flight.

A further characteristic of the invention is the elimination of the heretofore exclusively used and exceedingly heavy storage batteries. Storage batteries at best, if and when used on an airplane, are serviceable for periods of short duration only and must be removed and recharged after every flight. No one, in so far as I am aware, previously considered it practical or even possible to construct an electrical generator of sufficient Voltage, of the required light weight, and of the required small dimension to make it a serviceable unit capable of being advantageously installed on an airplane or other aircraft for the generation of suflicient electrical current to operate a plurality of lights. This I have succeeded, after prolonged experimentation, in doing. The electrical generator is preferably of the wind-driven type. Its total weight, supporting bracket and driving-propeller included, does not exceed forty pounds. It is mounted exteriorly of the machine directly behind and consequently wholly Within the slipstream of the airplane propeller. Thus mounted, the air directed rearwardly thru the operation of the airplane propeller, or the air set in motion thru thetranslation of the airplane thru the air, is relied upon to operate the driving pro- "peller'" of the generator. As long as the generator is in operation it is entirely practical to operate the Neon lights. Such continuity of operation is in no way limited to any specific time. If a flight of several hours duration is contemplated, and it is desired to continuously operate the advertising sign during the entire period of such flight, an electrical generator of the type mentioned will, withontquestion, and with a maximum of reliability, continuously generate more thansuflicient electrical current to properly and satisfactorily illuminate the sign throughout. No recharging is under any circumstances required; a large reduction in weight, forty pounds as compared to one hundred and eight pounds (one hundred and eighty pounds being the average weight of storage batteries) is obtained; and the generator in its entirety, because of its small size, may be perfectly streamlined to offer, during flight, a minimum of head resistance.

A still further characteristic of the invention is the extremely simple and exceptionall light means employed in fastening the Niion tubes or tube-lights in-place. Heretofore comparatively heavy and bulky metal fittings have been used for fastening the lamps and reflectors of the. conventional type advertising sign on the underside of the airplane wing or wings. This character of fastening, due to the light weight and small size of the tube-lights, 1s no longer required. A yielding fastening means is-provided instead. Preferably such fastening includes one or more soft rubber cushions for" each tube-light. Thesecushions are cemented or otherwise fastened directl to or against the fabric or other covering 0 the airplane wing and have imbedded, inserted or otherwise associated with or within them two or more wire hooks. The cushions above, and elastic bands or the like, stretched between the wire hooks, beneath, yieldingly and at the same time firmly hold the tube or tube-lights in. place. As. the tubes per se are extremely light, yielding fastening means of the character mentioned gives a safety factor ample at all times.

Other objects, advantages and improved results willbe hereinafter pointed out.

In the drawings wherein like reference characters denote like or corresponding parts,

Fig. 1 is aside elevation of an airplane equipped with an electrical advertising sign of the character herein disclosed;

Fig. 2 is an'inverted plan view of the airplane showing the arrangement of the Neon luminous tubes of lights;

Fig. 3 is a plan view of one of said tubes shaped to represent an alphabetical letter showing the continuity of outline required to be maintained;

Fig. 4 is an end elevation of an aeroplane wing having fastened therebeneath a tube light of the type herein referred to;

Fig. 5 is a perspective view of one of the tube fastening devices;

Fig. 6 is a transverse sectional view of the structure illustrated in Fig. 5;

Fig. 7 is a view in end elevation illustratlng a modified tube fastening means;

Fig. 8 is a similar view'of a further modification;

Fi 9 is yet another and similar view showmg a still further modification;

Fig. 10 is an enlarged section on the line 101O of Fig. 9;

Fig. 11 is a section on the line 11-711 of Fig 10, and

tig. 12 is a diagram of the electrical circu1 In the embodiment of the invention selected for illustration a more or less conventional type airplane is shown. It includes, in addition to the fuselage 10, wings 11, power plant (not shown) empennage 12, wing struts13 and landing gear 14, a drivmg propeller or tractor screw 15. Behind the propeller 15 and wholly within the slip stream thereof, is mounted .a wind driven electrical generator 16. Preferably the electrical generator is comparatively small, well streamlined throughout and of little weight. At its forward end it is provided with a small propeller 17 by means of which" it is driven; the air set in motion by the machine propeller and the air passing over its blades due to its translation thru space, constituting the driving force. Brackets 19, fastened to the wing struts 13, support the generator from beneath.

The letters or other characters comprising the advertising sign are fastened on the underside of the lower win or wings. Each letter, of which any num er'may be used, unless exceedingly large, is formed from a single length of glass or other translucent material tubing 20 such as is now used in the construction of the so-called' Neon luminous tube-lights. In the formation of each letter or other character, the tube material is permanently shaped by any well known process to conform in outline with the outline of the particular letter desired to be reproduced. In completing the letter outline, care should be exercised to effect a completion without a break in the continuity of the tube. It is also essential that the opposite ends of a given tube length be in no way joined. Each tube end, in the operation of the lights, may be said to provide one or the other of the positiveand negative terminals essential to the completion of the light circuit.

Illumination is made possible by passing either a high frequency current or a high voltage alternating current thru the tube or tubes. High frequency current may be obtained by passing the direct current from a generator thru a high frequency unit while the high voltage current may be obtained by passing an alternating currentfrom a generator thru a step-up transformer. The tubes themselves, however, and the means by which theyare continuouslyilluminated, form no part of the present invention. For a complete understanding thereof reference should be had to the Claude Neon United States patents numbered respectively, 1,125,476, 1,131,910,1,189,664,1,191,495 and 1,231,494.

When it is required, in the formation of a letter or other character, that certain portions of a given tube length shall lie contiguous and parallel, as. for example in the formation of the letter E, that portion ofthe tube length lying contiguous to a correspondingly disposed portion should-be so coated or otherwise treated as to render it opaque.- In thus obliterating all duplicate or contiguous portil'nsof the continuous line of light, a better letter or character outline is produced. Fig. 3 of the drawings illustrates what is meant by obliterating a portion of the light. If desired'fi'but primarily to avoid tube breakage and head resistance, the ends of the tubes 26 may besi-nturned as indicated at 21.

In, ff-grouping of the letters, or rather the tubeil gh s comprising them, a symmetrical arrangement is preferable Two letters or tubes 20 constitute, in the arrangement shown, a single group or series. In passing the electrical current from-the generator 16 to the separate series (one at either side of the fore and aft axis of the machine) two step-up transformers 22 are used. One of said transformers 22 is in series with the two tubes comprisingthe right hand group of letters and the other of said transformers is similarly in series with the left. But a single letter or tube, or three or more letters or tubes, if circumstances require, may be connected in series rather than two. Also, if desired, a choke-coil 22 may be interpolated in the electrical circuit to equalize the amount of current supplied to the separate series of lights. In Fig. 12 of the drawings the preferred circuit arrangement is diagrammatically shown.

From actual flight tests, repeatedly conducted, it has been found that by using a generator, one or more transformers, and one or more luminous tube-lights, in combination, there is produced penetrating, non-glaring, sharply defined and unbroken line-light having a pronounced reddish tint or color. Such a light, used for night aerial advertising purposes, is vastly superior to the non-penetrating, glaring and broken line white light now obtained thru the use of incandescent lamps or bulbs. Compared to a white light, a red light of e ual volume or intensity, is visible to the na ed eye at a greater distance. This increased visibility, in the use of a red line-light becomes evenmore apparent when used onaircraft at high altitudes due to the increasing rarity of the air and itsfreedom from ground dust and smoke.

in the tubes a decidedly The means for fastening or attaching the tube-lights or tubes 20 to the aircraft, is such in its nature as to prevent at all times breakage of the tubes due to vibrations and shocks in the operation of the machine. It is also ing surface against which the tubes are yieldingly held. The hooks 26 are either inserted or imbeddedin the cushions, and may or may not be formed from a single wire length. ,In spacing them, one at each side of the tube, and extending an elastic band 27 from the one to the other thereof on the opposite side of the tube from that in bearing contact from the cushion, a positive and at the same time a yielding means is provided for firmly holding the tube against the cushion and firmly tho yieldingly in place upon the airplane wing.

In the-modified form of fastening illus trated in Fig. 7, no hooks, such as are indicated at 26 in Fig. 6, are used. An endless wire 28 encircles the wing in a fore and aft direction. Between it (the wire 28) and the undersurface of the wing, one or more cushions 29 are interposed. As in the preferred disclosure the cushions 29 provide a soft hearing surface for the tubes. Elastic bands 30, fastened around both the tubes and the wire 28, at opposite sides of the cushion, hold the tubes yieldingly against the cushions at all times.

In Fig. 8 of the drawings a fastening means, of extreme simplicity and light weight is disclosed. As in the fastening of Fig. 7, a wire-28' is provided. The wire 28 is extended along the undersurface of this wing, in a fore and aft direction, from its leading to its trailing edge. It is fastened to said edges by clips 28" extended thereon. No cushions, between the wire and the wing, need be used. Only such cushions as have been designated as 29 are required. These cushions merely hold the tube-lights against is shown.

direct bearing contact with the wire 28'. Elastic bands 30 passing under the tubes and over the wire complete this form of fastening. To reinforce the tubes in a direction at right angles to the line of flight a wire may be, if required, extended longitudinally of the wing.

In the modification of Figs. 9, 10 and 11 a somewhat different character of fastening Provision is made in this type fastening for certain adjustments tending to admit of the use of the same fastening means for tubes or letters of different size. Small strips 31 of wood or metal are mounted on. the underside of the wing. These strips 31 are preferably straight and are extended in a fore and aft direction to provide for the tubes or letters a level base regardless of the curvature of the wing. They are held in place by clips 32, front and rear, extending up and over the leading and trailing edges respectively of the wing. One of said clips is made freely slidable longitudinally of the strip to admit of its use upon wings of varying chord length. In addition to the clips 32 each strip is provided with'di'sc like fittings 33 having spaced upstanding ears 34 between which the opposite faces of the strip are adapted .to engage. Each fitting 33 is also provided, on its underface, with a cushion 35. A wire 36, of inverted U-shape, extends over the strip 31, the bight portion of the U- shaped wire being in engagement with that face of the strip adjacent to the undersurface of the wing. The arms or side extensions of said wire are carried outwardly or away from the wing and penetrate both the fitting and the cushion, each arm terminatingin a hookend, An elastic band 37 extended from one to the other of the wire ends, and across or over the tube, completes the tube fastening means. As in the previously described fastening's, the tubes or letters are yieldingly tho firmly held. The fittings 33, wires 36, cushions 35 and elastic bands 37, are slidable as a unit lengthwise the strip 31.

'- An electrical advertising sign, fastened as above described, when used on or in connection with an airplane or' other aerial craft, effects thru such use, a big saving in weight and head resistance. The light weight tubes, the absence of light reflectors, the elimination of the use of storage batteries, and the continuity of letter outline, all contribute very materially to this end. In using a non- 4 heat generating light (within certain limits) rubber may be directly applied, as a fastening means, upon the tubes. In using a non filament light the worries incident to the replacement of damaged or burntout bulbs are eliminated. Mechanical complications, arising from the use of reflectors, are avoided. The lift efliciency of the wing or wmgs (when used on an airplane) is but slightly, if to any appreciable degree, impaired. Flights, for display purposes may be made at any height or altitude desired. The dangers of low altitude flying over thickly populated centers (essential where the old method is used) have been overcome. A continuity of luminous letter outline, as distinguished from a broken line-light, is obtained. A greater number of persons, for a given display, are brought within seeing and reading distance of the sign. A penetrating, nonglaring reddish light, as distinguished from a non-penetrating glaring fulhwhite light,

an le.

is produced at all given display, instead of being dependent upon fully charged or partly discharged batteries is limited only by the fuel capacity of the machine. And last, but not least, that which has heretofore been considered dan-. gerous and impractical, is made, thru the combination of devices herein disclosed, both entirely safe andentirely practical, as well as vastly'superior, considered from'any ile Ijhave described my invention in detail in its present preferred embodiment, it will be obvious to those. skilled in the art after understanding my invention, that various changes and modifications may be made therein without departing from'thespirit or scope thereof. I'aim in the appended claims to cover all such modifications and changes' I What Iclaim isz' l. The combination with a power driven aeroplane, of an electrical aerial advertising sign or the like comprising one or more luminous tube lights, each consisting of a single 1 length of translucent tubing shaped 'to conform either in whole or input to the outline of the letter or other character desired to be shown, means for fastening saidtube lights on the underside of the wings of said aero-L plane, and a wind driven electrical generator mounted on said aeroplane and electrically 1 connected with said light or lights for generfastenin ating sufficient current to operate itor them. 2 Q

2. The combination, with a power driven aeroplane, of an electrical aerial advertising sign or the like comprising one or more lumiw nous tube. lights, each consisting of a single length of translu'centtubing shaped to con.

form either in whole or in part to the outline of the letter or other character desired to be shown, vibration shock absorbing means for erate it or them.

3. The combination with a power driven aeroplane, of an electrical aerial advertising sign orthe like comprising one or more luminous tube lights,.each consisting of a single length-of translucent tubing shaped'to conform-either in whole or in part to the outline of the letter or other character desired to be In testimony whereof I hereunto aflix my signature.

ROLAND ROHLFS.

times. The duration of a said tube lights on theunder side of the wings of said aeroplane, and an electrical generator mounted on said aeroplane and electrically connected with said light or lights for generating suflicient current to op- 

